Filter Device, Especially Liquid Filter

ABSTRACT

A filter device comprises a hollow cylindrical filter element in a filter housing. The fluid that is to be purified is to radially flow through the filter element. The interior of the filter element forms an axial flow chamber for the fluid. An end plate is arranged on the front side of the filter element. An annular neck, onto which a sealing element is injection-molded, is connected to the end plate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/335,898, filed Jul. 19, 2014, which is a continuation of U.S.application Ser. No. 12/810,198 filed Oct. 12, 2010, which is acontinuation of PCT/EP2008/067904, filed Dec. 18, 2008 designating theUnited States of America, and a continuation in part of U.S. applicationSer. No. 12/332,612, filed Dec. 11, 2008, now U.S. Pat. No. 8,157,107.The entire disclosure of the above applications is incorporated hereinby reference. Priority is claimed based on German patent application 202007 018 076.4 filed in Germany on Dec. 21, 2007 and German patentapplication 20 2007 017 614.7 filed in Germany on Dec. 14, 2007

TECHNICAL FIELD

The invention concerns a filter device, especially a liquid filter, suchas a fuel filter or oil filter, according to the preamble of claim 1.

PRIOR ART

A filter device that is used as an oil filter or a fuel filter isdisclosed in DE 197 46 752 A1. The filter device comprises a hollowcylindrically embodied filter element that is secured on a radiallyinwardly positioned support structure and is flowed through by the fluidto be purified radially from the exterior to the interior wherein thefilter interior forms an axial discharge passage for the purified fluid.The filter element is framed by terminal disks at the end faces thathave a central cutout for discharging the fluid from the filterinterior. In the central cutout of the terminal disk a sealing ring isinserted that is supported on an inner housing wall and separates theaxial discharge space from the inflow side of the filter element. Suchsealing elements are mandatorily required for a flow-tight separation ofraw side and clean side.

SUMMARY OF THE INVENTION

The invention has the object to separate with simple means and in aspace-saving as well as effective way the raw side from the clean sidein a filter device.

This object is solved according to the invention with the features ofclaim 1. The dependent claims provide expedient further embodiments.

The filter device has in a filter housing a hollow cylindrical filterelement that is to be flowed through by the fluid to be purified inradial direction. The interior of the filter element forms an axial flowspace. At one end face of the filter element there is a terminal diskwhere the sealing element is arranged. According to the invention, thissealing element is injection-molded onto an axially projecting, annularsocket that is connected to the terminal disk.

With this embodiment different advantages are achieved. Byinjection-molding the sealing element separate assembly steps are nolonger required that in an embodiment of the sealing element as its owncomponent, in particular as a sealing ring, would be otherwise required.In the embodiment according to the invention, it is instead sufficientto injection-mold, before mounting the filter device, the sealingmaterial onto the annular socket; subsequently, the filter elementincluding sealing disk and socket together with the injection-moldedsealing element can be inserted into the filter housing. Leakage flowscaused by mounting are prevented in this way.

Moreover, the stability of the filter device is improved because forcesin the axial direction are transmitted substantially from the socketonto the filter housing. This means that the sealing element ispositioned between the end face of the socket and the inner wall of thefilter housing; since this section of the sealing element is howeverusually very thin-walled, a tilted positioning of the filter device thatcould lead to leakage flows is not to be expected as a result of thedeformation of the sealing element.

According to an advantageous embodiment, the sealing element iscomprised of an injection-moldable silicone material, in particular afluorosilicone rubber (FVMQ) that is characterized by an excellent fuelresistance, in particular by excellent diesel fuel resistance andtherefore in a special way is suitable for use in fuel filters.

According to a further advantageous embodiment, the socket has shapedelements that contribute to an improved adhesion of the sealing materialon the socket. These shaped elements change the surface of the socketand are embodied as projections or, according to a preferred embodiment,as cutouts in the wall of the socket. In the embodiment as cutouts, theycan be distributed uniformly about the circumference of the socket.During the injection molding step, the sealing material will deposit onthe shaped elements so that an additional resistance with respect toaccidental removal of the sealing material from the socket is provided.In case of the cutouts in the wall of the socket, the cutouts areadvantageously completely filled with the sealing material so that noleakage flows through these cutouts may occur.

The sealing material is expediently injection-molded onto the innerside, the outer side as well as the free end face of the socket so thatthe best possible sealing action is achieved. Even though, it is inprinciple sufficient to provide the sealing material only on the innerside or only on the outer side or optionally to provide the sealingmaterial only on the end face of the socket or on a combination of endface and inner side or outer side of the socket.

The annular socket in its simplest embodiment is a cylinder whose sidewalls and free end face form the support for the sealing material.However, other geometries may be provided also for the socket, forexample, a socket with a cylindrically shaped section and a furthersection angularly extending therefrom or a socket with a slantedlyextending wall that is positioned at an angle to the plane at theterminal disk. The sealing material may extend either about the entireinner side and outer side of the socket or, according to a furtherembodiment, only across a partial area of the socket, for example, onthe angularly projecting section of the socket.

According to yet another advantageous embodiment, two concentric socketsare provided that are spaced apart radially from one another wherein thesealing material is injection-molded onto both sockets. Since each oneof the two sealing elements is provided with a sealing line, the sealingaction is improved.

The socket is advantageously embodied as a monolithic part of theterminal disk; both components can be manufactured of injection-moldableplastic material. Basically, it is however also possible to embodysocket and terminal disk as two separate components that are connectedto one another

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and expedient embodiments may be taken from theadditional claims, the figure description, and the drawings. It is shownin:

FIG. 1 a perspective view of the lower part of a filter device with ahollow cylindrical filter element whose end face is framed by a terminaldisk that is provided with a central cutout for discharging the purifiedfluid, wherein the central cutout is surrounded by a socket onto whichsealing material is injection-molded;

FIG. 2 a section view of the filter device according to FIG. 1 in thearea of the socket;

FIG. 3 a section illustration of a further embodiment according to whichtwo sockets concentrically arranged relative to one another are providedonto which sealing material is injection-molded, respectively;

FIG. 4 a further embodiment in which the socket has additionally anangularly arranged section that is a support for the sealing element;

FIG. 5 a further embodiment in which the socket is comprised of aslantedly extending wall that is formed monolithically with the terminaldisk; and

FIG. 6 a section view of a filter device having two socketsconcentrically arranged relative to one another and onto which sealingmaterial is injection-molded, respectively;

EMBODIMENTS OF THE INVENTION

In the Figures the same components are identified with same referencenumerals.

The filter devices illustrated in the Figures are suitable forfiltration of liquid or gaseous fluids, in particular for filtering fuelsuch as diesel fuel or oil. Also, a use, for example, as an air filteris possible.

The filter device 1 illustrated in FIG. 1 comprises a hollow cylindricalfilter element 2 in a filter housing 3 wherein the filter element 2 isflowed through radially from the exterior to the interior by the fluidto be purified so that the outer wall surface represents the raw sideand the axial interior in the filter element represents the clean sidefrom where the purified fluid is discharged axially through the endface. The axial end face of the filter element 2 is framed by a terminaldisk 4 that has a central cutout 5 that communicates with the axialinterior of the filter element 2. In the central cutout 5 a cylindricalsocket 6 is inserted that advantageously is monolithically formed withthe terminal disk 4. In the wall of the socket 6 a plurality of cutouts7 are provided that are distributed uniformly about the circumferenceand penetrate the wall. The socket 6 is a support for a sealing element8 that is comprised of an injection-moldable material, in particular ofa silicone material such as partially fluorinated liquid silicone (FVMQ)and is injection-molded onto the socket 6. The sealing material islocated on the outer side, the inner side and the free end face of thesocket 6 and covers also completely the cutouts 7 in the wall of thesocket 6. The cutouts 7 have the function of shaped elements that ensureimproved adhesion of the sealing material on the socket 6.

The selection of the sealing material depends on the fluid to bepurified. For use as a diesel fuel filter, advantageously theaforementioned material FVMQ is used that is characterized by high fuelresistance while at the same time providing excellent injection moldingproperties.

As illustrated in the section view of FIG. 2, the socket 6 is formedmonolithically with the terminal disk 4. The sealing element 8 has twocontact lines: on the one hand, in the area of the free end face on thesocket 6 and, on the other hand, at the transition area between socket 6and terminal disk 4 on the side facing away from the central cutout 5.In the area of the two contact lines the sealing element 8 has a greaterwall thickness. In order to design the seal to be more resistant withregard to high pressure peaks, in a supplemental embodiment acircumferentially extending reinforcement ring may be provided in thearea of the seal support. This ring is positioned circumferentiallybelow or on the seal 8. There is also the possibility to employhigh-strength sealing materials or sealing materials that have a hightear resistance.

In the embodiment according to FIG. 3, on the terminal disk 4 a secondsocket 9 is provided that extends concentrically relative to the firstsocket 6 but in comparison to the first socket 6 has a smaller diameter.Also, the axial extension of the second socket 9 is less than that ofthe first socket 6. The second socket 9 is also formed as a monolithicpart with the terminal disk 4 as is the first socket 6. The sealingelement 8 is injection-molded onto the first socket 6 as well as ontothe second socket 9 and extends along the inner side of the first socket6, on the inner and outer sides of the second socket 9 as well as in theintermediate area on the terminal disk 4 between first and secondsockets 6 and 9, forming a generally U-shaped sealing element 8, asshown in FIG. 3. Moreover, the two free end faces of the sockets 6 and 9are covered with sealing material. The sealing element 8, at the freeend faces of the sockets 6 and 9, has a greater wall thickness, formingbulbous shaped sealing members 8A, 8B on the free end faces of thesockets 6 and 9, as clearly shown in FIG. 3. The wall of the firstsocket 6 and second socket 9 may include a plurality of cutouts 7 (seeFIG. 1) distributed uniformly about the circumference and penetratingthe wall. The cutouts 7 (see FIG. 1) have the function of shapedelements that ensure improved adhesion of the sealing material on thesockets. The sealing material may be located on the outer side, theinner side and the free end face of the sockets cover also completelythe cutouts in the wall of the sockets, if present.

There are a total of two sealing lines between the sealing element 8 andthe filter housing or the components of the housing; both sealing linesare located in the area of the free end faces of the sockets 6 and 9.

In the embodiment according to FIG. 4, the cylindrical socket 6 in thearea of its end face is provided with a section 6 a that is radiallyinwardly angled at a 90 degree angle whose free end face is a support ofthe injection-molded sealing element 8.

In the embodiment according to FIG. 5 the socket 6 that is a monolithicpart with the terminal disk 4 is angularly embodied; it is positionedrelative to the plane of the terminal disk 4 at an angle deviating from90 degrees and is oriented radially outwardly. The sealing element 8that is injection-molded on the socket 6 engages the end face of thesocket as well as the inner side and the outer side and has a relativelycomplex cross-sectional geometry. Two sealing lines are formed by meansof which the sealing element 8 is seal-tightly supported on a furthercomponent of the filter device.

Similar to the embodiment of FIG. 3, referring now to the embodiment ofFIG. 6, on the terminal disk 4 a second socket 9 is provided thatextends concentrically relative to the first socket 6 but in comparisonto the first socket 6 has a smaller diameter, as in FIG. 3. In FIG. 6the axial extension of the second socket 9 may be substantially the sameas that of the first socket 6. The second socket 9 is also formed as amonolithic part with the terminal disk 4 as is the first socket 6. Thesealing element 8 may be injection-molded onto the first socket 6 aswell as onto the second socket 9 and extends along the radially outerside of the first socket 6, on the radially inner side of the secondsocket 9, and may extend on the intermediate area on the terminal disk 4between first and second sockets 6 and 9, forming a continuous annularsealing element 8, as shown in FIG. 6. Moreover, the two free end facesof the sockets 6 and 9 are covered with sealing material. The wall ofthe first socket 6 and/or the second socket 9 may include a plurality ofcutouts 7 (see FIG. 1) distributed uniformly about the circumference andpenetrating the wall. The cutouts 7 (see FIG. 1) have the function ofshaped elements that ensure improved adhesion of the sealing material onthe sockets. The sealing material may be located on the outer side, theinner side and the free end face of the sockets cover also completelythe cutouts in the wall of the sockets, if present. A drain passage 14is shown, separated by a double-concentric seal 15 from the filteredside as well as from the unfiltered side of the filter element 2. Thedouble-concentric seal 15 may be produced by a two-component method, forexample, by injection molding a combination of hard and soft sealingmaterials.

1. A filter device for filtering a liquid, comprising: a hollowcylindrical filter element (2) for arrangement in a filter housing (3)that is radially to be flowed through by the fluid to be purified;wherein an open interior of the filter element (2) forms an axial flowspace for the fluid in the interior; the filter element furthercomprising: a terminal disk (4) arranged on an axial end face of thefilter element (2), the terminal disk having an open central portionopening through the end disk into the interior; a first axiallyprojecting annular socket (6) having a first axial end secured onto theterminal disk, the first annular socket including an axially outwardlyprojecting annular wall (6) circumferentially surrounding the opencentral portion; and a sealing element arranged on the first annularsocket over at least a portion of the annular wall, the sealing elementoperative to form a seal between the terminal end disk (4) and thefilter housing to seal between a raw side and a clean side of the filterelement; wherein the sealing element comprises sealing material (8)injection-molded onto the first axially projecting annular socket (6); asecond axially projecting annular socket (9) having an axial end securedonto the terminal disk (4) and arranged concentrically to the firstsocket (6), the second annular socket (9) including an axially outwardprojecting annular wall surrounding the open central portion; and asealing element arranged on the second annular socket (9) over at leasta portion of the annular wall, the sealing element operative to form aseal between the terminal end disk (4) and the filter housing (3);wherein the sealing element comprises sealing material (8)injection-molded onto the second annular socket.
 2. The filter device ofclaim 1, wherein the axially projecting annular sockets are formedmonolithically and in one piece with the terminal disk.
 3. The filterdevice of claim 1, wherein the sealing material is comprised of asilicone material.
 4. The filter device of claim 3, wherein the siliconematerial is a fluorine-silicone-rubber (FVMQ).
 5. The filter device ofclaim 1, wherein at least one of the annular sockets includes shapedelements formed thereon and configured to improve adhesion of thesealing element onto the annular socket.
 6. The filter device of claim5, wherein the shaped elements are embodied as cutouts extendingradially through and formed into the annular wall of at least one of theannular sockets.
 7. The filter device of claim 1, wherein the sealingmaterial is injection-molded onto the inner side, the outer side, andthe free end face of the sockets.
 8. A hollow cylindrical filter element(2) for filtering a liquid for arrangement in a filter housing (3),wherein the filter element (2) is radially to be flowed through by afluid to be purified; wherein an open interior of the filter element (2)forms an axial flow space for the fluid in the interior; the filterelement comprising: a terminal disk (4) arranged on an axial end face ofthe filter element (2), the terminal disk having an open central portionopening through the end disk into the interior; a first axiallyprojecting annular socket (6) having a first axial end secured onto theterminal disk, the first annular socket including an axially outwardlyprojecting annular wall (6) circumferentially surrounding the opencentral portion; and a sealing element arranged on the first annularsocket over at least a portion of the annular wall, the sealing elementoperative to form a seal between the terminal end disk (4) and thefilter housing to seal between a raw side and a clean side of the filterelement; wherein the sealing element comprises sealing material (8)injection-molded onto the first axially projecting annular socket (6); asecond axially projecting annular socket (9) having an axial end securedonto the terminal disk (4) and arranged concentrically to the firstsocket (6), the second annular socket (9) including an axially outwardprojecting annular wall surrounding the open central portion; and asealing element arranged on the second annular socket (9) over at leasta portion of the annular wall, the sealing element operative to form aseal between the terminal end disk (4) and the filter housing (3);wherein the sealing element comprises sealing material (8)injection-molded onto the second annular socket.